Re: Incomming mail transfered via alia get rejected

Email 'user_alias@qsl.net' is hosted on your iRedMail server, so if an email sent as 'user_alias@qsl.net', Postfix will force sender to perform SMTP authentication to send this email. Obviously, you didn't do this, that's why Postfix rejected your email and your sender got this bounce message.

Re: Incomming mail transfered via alia get rejected

But user_alias@qsl.net is not hosted on my iRedMail server, firstname.lastname@mydomain_a.com is, and mailman.qth.net tries to forward a mail sendt to user_alias@qsl.net to firstname.lastname@mydomain_a.com (on my server)...

Re: Incomming mail transfered via alia get rejected

Message "Sender address rejected: not logged in" always means the sender address in this email is hosted on your server, so you have to figure it out why this email has this sender address.

By the way,

*) What's the original sender address? Show us the real email address, but replace some characters by '*'. for example, user@gm***.com. *) Is sender hosted on mailman.qth.net? Or user_alias@qsl.net is?